1. Field of the Invention
The present invention relates to a transportation device of a withdrawable circuit breaker, and more particularly, to a transportation device of a withdrawable circuit breaker capable of simultaneously moving right and left handles of a girder assembly for restricting movement of the transportation device or releasing a restricted state of the transportation device.
2. Background of the Invention
Generally, a circuit breaker is installed at a distribution board provided to drive or control a power plant, a substation, etc., or to drive a motor, with other electric devices. The circuit breaker is generally accommodated in a cradle fixed to the distribution board.
The cradle has a service position and a test position therein. The service position indicates a position where a voltage and a current are supplied as a terminal of a body of the circuit breaker is connected to a terminal of the cradle, and the test position indicates a position where only an operation test of the circuit breaker is executable as the terminal of the body of the circuit breaker is separated from the terminal of the cradle.
An operation to insert the circuit breaker so as to connect with a line part of the cradle is called an ‘insert’ operation, and an operation to withdraw the circuit breaker is called a ‘pull out’ operation.
FIG. 1 is a perspective view of a circuit breaker in accordance with the conventional art, which shows a mounted state of a body 1 of the circuit breaker and a transportation device 2 to a cradle 3. The body 1 of the circuit breaker is partially shown. That is, the body 1 having a front cover removed therefrom is shown. Such a box-shaped cradle is called a distribution box. FIG. 2
FIG. 2 is a perspective view of the transportation device 2 of FIG. 1, and FIG. 3 is a perspective view illustrating a removed state of a body plate 21 of a girder assembly 20 in FIG. 2. The body 1 of the circuit breaker is moved in a loaded state on the transportation device 2. Once a lead screw 11 is rotated by inserting a handle (not shown) into a handle groove 12 of the girder assembly 20 connected to a front surface of a truck assembly 10, an insert operation or a pull-out operation of the body 1 of the circuit breaker occurs while the truck assembly 10 is moving. In this case, the girder assembly 20 is fixed to a rail 5 of the cradle 3.
FIGS. 4A and 4B illustrate operation positions of handles of the transportation device 2. FIG. 4A shows a restricted state implemented as sliding plates 22, 23 of the transportation device 2 are inserted into rail grooves 4 of the cradle 3, and FIG. 4B shows a released state implemented as the sliding plates 22, 23 are separated from the rail grooves 4 of the cradle 3.
In case of separating the body 1 of the circuit breaker from the inside of the cradle 3 to the outside, handles 25, 26 of the girder assembly 20 should be inward moved, and the sliding plates 22, 23 connected to the handles 25, 26 should be separated from the rail grooves 4.
Handle assemblies 22,25 and 23,26 are coupled to the girder assembly 20. The handle assemblies 22,25 and 23,26 have an integral structure as the left and right sliding plates 22, 23 are coupled to the left and right handles 25, 26, respectively.
The left and right handles 25, 26 are simultaneously pushed toward the inside such that the left and right sliding plates 22, 23 are separated from the rail grooves 4. Then, the body 1 of the circuit breaker may be transferred to the outside of the cradle 3.
However, the conventional transportation device of the circuit breaker may have the following disadvantages.
Firstly, the handle assemblies 22,25 and 23,26 are formed so as to be moved individually. As a result, only one sliding plate 23 may be separated from the rail groove 4, while the other sliding plate 22 remains as it is by a user's mal-operation, etc. FIG. 5 is a view illustrating an abnormally separated state of the circuit breaker from the cradle. FIG. 6 is a front perspective view of the girder assembly in FIG. 5. FIG. 7 is a rear perspective view of the girder assembly 20 in FIG. 5. The body 1 of the circuit breaker may not be separated from the inside of the cradle 3 to the outside, and damage of the components or accidents may be caused.